1. Field of the Invention
This invention generally relates to an alternator for a vehicle such as a passenger car or a truck. This invention particularly relates to the structure of a terminal for connection between an armature-coil lead and a rectifier assembly in an alternator.
2. Description of the Related Art
UK patent application GB 2235822 A (corresponding to Japanese patent application publication number 3-107356) discloses a rectifier assembly for motor vehicles. In UK patent application GB 2235822 A, the rectifier assembly has positive and negative diodes respectively inserted by their housings into two metallic, mutually parallel cooling plates between which is disposed a printed circuit board for connecting the diodes to one another as well as to wires of a stator winding of the alternator. On the front, positive cooling plate, there is a radially outwardly guided positive terminal, which comprises a retaining plate and a bolt, and which is fastened thereto and projects radially beyond the cooling plates.
The retaining plate is riveted by spaced rivets onto the front cooling plate, and a plastics part is formed onto the outer edge of the circuit board to accommodate the limb of the retaining plate.
In UK patent application GB 2235822 A, using a plurality of external crimped connectors in the printed circuit board, the diodes are electrically connected to connecting wires of a stator winding of the alternator. Each of the crimped connectors has an exposed U-shaped portion. In order to provide the necessary space in the region of the positive terminal, the limb of the retaining plate is provided between the rivets with an opening, through which one of the crimped connectors passes to the front for contacting a connecting wire of the stator winding with the conductors in the printed circuit board. The crimped connector passing through the opening of the retaining plate is embedded in a sleeve, which is formed onto the printed circuit board and which engages in a corresponding recess of the two cooling plates.
The rectifier assembly and the stator winding vibrate as the body of a related motor vehicle vibrates. In UK patent application GB 2235822 A, both the vibration of the rectifier assembly and the vibration of the stator winding are transmitted to the crimped connectors. Since the rectifier assembly and the stator winding occupy separate portions in the alternator, the vibration of the rectifier assembly and the vibration of the stator winding have different frequencies respectively. Thus, a phase difference between the vibration of the rectifier assembly and the vibration of the stator winding causes stresses to be applied to the crimped connectors. Such stresses adversely affect the crimped connectors. The strength of the stresses increases as the level of the vibration of the vehicle body rises.
Japanese patent application publication number 5-49221 (application number 3-196380) discloses an alternator for a vehicle in which an extension of an armature coil is connected to a thin-wall terminal projecting from and supported by a rectifier assembly. The extension of the armature coil is firmly held by the terminal as a result of pressing and deforming the walls of the terminal. A great stress tends to be applied to the terminal when the body of the vehicle vibrates at a high level. Such a stress adversely affects the terminal.
It is an object of this invention to provide an alternator for a vehicle which includes a terminal having a strong or rugged structure.
A first aspect of this invention provides an alternator for a vehicle. The alternator comprises a stator (2); an armature coil (21) wound on the stator (2); a rectifier unit (5) including a terminal base (55); and a connection terminal (51) electrically connected with the armature coil (21) and extending into the terminal base (55); wherein the connection terminal (51) includes an exposed portion (511) having a U-shaped cross-section and emerging from the terminal base (55); the exposed portion (511) has a groove (512) designed so that at least two of three sides of the U-shaped cross-section remain; and the exposed portion (511) has an end electrically connected with the armature coil (21).
A second aspect of this invention is based on the first aspect thereof, and provides an alternator wherein the two of the three sides of the U-shaped cross-section form a corner (513).
A third aspect of this invention is based on the first aspect thereof, and provides an alternator wherein a part of the groove (512) is located in a wall of the terminal base (55).
A fourth aspect of this invention provides an alternator for a vehicle. The alternator comprises a stator (2); an armature coil (21) wound on the stator (2); a rectifier unit (5) including a terminal base (55); and a connection terminal (51D) electrically connected with the armature coil (21) and extending into the terminal base (55); wherein the connection terminal (51D) includes an exposed portion (511D) having a U-shaped cross-section and emerging from the terminal base (55); the connection terminal (51D) has a buried portion having a U-shaped cross-section and located in a wall of the terminal base (55); and the buried portion of the connection terminal (51D) has a groove (512D) designed so that at least two of three sides of the U-shaped cross-section remain.
A fifth aspect of this invention is based on the first aspect thereof, and provides an alternator wherein the electrical connection between the armature coil (21) and the connection terminal (51) is provided by a welding process.
A sixth aspect of this invention is based on the first aspect thereof, and provides an alternator wherein the electrical connection between the armature coil (21) and the connection terminal (51) is provided by a crimping process.
A seventh aspect of this invention is based on the fifth aspect thereof, and provides an alternator wherein the welding process is of a TIG type.
An eighth aspect of this invention is based on the first aspect thereof, and provides an alternator wherein the armature coil (21) includes an electric conductor having a flat type cross-section.
A ninth aspect of this invention provides an alternator for a vehicle. The alternator comprises a stator (2); an armature coil (21) wound on the stator (2); a rectifier unit (5) including a terminal base (55); and a connection terminal (51E, 51F, 51G, 51H) electrically connected with the armature coil (21) and extending into the terminal base (55); wherein the connection terminal (51E, 51F, 51G, 51H) has an L-shaped cross-section; the connection terminal (51E, 51F, 51G, 51H) includes an exposed portion (511E, 511F, 511G) projecting from the terminal base (55); and the exposed portion (511E, 511F, 511G) has an end electrically connected with the armature coil (21).
A tenth aspect of this invention is based on the ninth aspect thereof, and provides an alternator wherein the electrical connection between the armature coil (21) and the connection terminal (51E, 51F, 51G, 51H) is provided by a welding process.
An eleventh aspect of this invention is based on the tenth aspect thereof, and provides an alternator wherein the welding process is of a TIG type.
A twelfth aspect of this invention is based on the ninth aspect thereof, and provides an alternator wherein the armature coil (21) includes an electric conductor having a flat type cross-section.
A thirteenth aspect of this invention is based on the ninth aspect thereof, and provides an alternator wherein the exposed portion (511G) has an L-shaped cross-section, and is formed with a cut (512G) designed to leave two sides of the L-shaped cross-section.
A fourteenth aspect of this invention is based on the ninth aspect thereof, and provides an alternator wherein the connection terminal (51H) has a portion embedded into the terminal base (55) and being of an L-shaped cross-section, and the embedded portion has a cut (512H) designed to leave two sides of the L-shaped cross-section.